Regulators, or converters, including a switch for transferring energy from an input or supply power source, such as an AC or DC voltage or current source, to a regulated output arc well known. An important specification of regulators is the desired average output level, which may be referred to as the regulation point. The regulation point is generally specified to have a permissible range to which the regulator will maintain the output over specified conditions, such as load and temperature conditions, as well as over process and circuit variations, such as offsets and gain errors. When the regulator is able to maintain the output within the permissible range, the regulator may be described as maintaining regulation; whereas, when conditions prevent the output from being maintained within the permissible range, the regulator may be described as being unable to maintain regulation.
Voltage and current regulators are used in a variety of sensor applications, including many safety critical applications, such as in automobiles. There are a variety of industry specifications that set forth requirements related to permissible sensor quality levels, failure rates, and overall functional safety. One such application is magnetic field sensors that include one or magnetic field sensing elements, such as a Hall effect element or a magnetoresistive element, to sense a magnetic field as may be associated with proximity or motion of a target object, such as a ferromagnetic object in the form of a gear or ring magnet, or to sense a current, as examples.
A typical regulator requirement is the detection of when the regulator begins to degrade as a result of reduced supply voltage. Such under voltage detection is often achieved with the use of a fixed threshold for comparison to the regulated output. Selection of the threshold requires careful consideration of process variables and can result in use of a threshold that is higher than the level where the regulator performance actually begins to degrade.